1. Field of the Invention
The present invention relates to a gun system, and an ammunition handling system for a gun. More particularly, the present invention relates to a shell casing unloading device used in the ammunition handling system of a high rate of fire automatic gun.
2. Description of the Related Art
Automatic high rate of fire guns, for example 20 mm M61A1 Gatling-type guns used in fighter aircraft, are mated with ammunition handling systems that deliver a steady supply of rounds to the gun (each round including a shell and a brass shell casing), remove the spent shell casings from the gun, and store the spent shell casings to preclude their ingestion by the aircraft's engine(s).
FIG. 1 depicts an ammunition handling system used with a high rate of fire gun. A continuous conveyor belt 21 feeds rounds into a storage drum 22. The rounds leaving the drum are reinserted into the conveyor belt, then fed via a loading sprocket 24 into a gun 26. Each round includes a shell 27 and a shell casing 28. An unloading sprocket 30 takes the spent shell casings 28 from the gun 26. Unloading sprocket 30 rotates within the housing of a transfer unit 31.
FIG. 2 depicts a conventional unloading sprocket 30. The sprocket 30 includes a forward sprocket 32 and an aft sprocket 34. The two sprockets are fixed together by a hub 36, and therefor rotate in unison.
FIG. 3 broadly depicts the aft end "a" of a shell casing 28 and the forward end "f" of the shell casing.
In normal operation, high rate of fire gun mechanisms are subjected to severe accelerations in multiple directions. When subjected to such accelerations, the forward end "f" of shell casing 28 in the conventional unloading sprocket 30 can become bound between the forward sprocket 32 and a gun guidebar. This interference can result in the forward end "f" of shell casing 28 being dented.
Dented shell casings may be deformed to an extent that is physically incompatible with the high speed mechanisms contained in the ammunication handling system, causing these mechanisms to jam and, in some instances, be damaged as the dented shell casing is processed through them. In an extreme case, this damage may render the gun system inoperable.